Forty patients undergoing dialysis treatment will be evaluated by analyzing serum specimens obtained during outpatient hemodialysis access. Serum will also be collected from ten pre-dialysis patients and ten normal volunteers for comparison. Pre-dialysis patients are those who have Stage 3, 4, or 5 chronic kidney disease but are not yet on dialysis and have never had any type of created vascular access. Normal subjects will have no kidney disease, autoimmune disorders, recent (<6 months) chemotherapy treatment or corticosteroid use, or other chronic condition determined by the investigator to interfere with cytokine and inflammatory markers. The serum specimens will be analyzed for cytokine/inflammatory markers and correlated with clinical access type and other medical data and demographic information.